CVE-2021-3593

An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality.

This flaw does not affect the versions of SLiRP embedded in qemu-kvm as shipped with Red Hat Enterprise Linux 6 and 7, because support for udp6 was introduced in a later version of the package. A future update may address this issue in Red Hat Enterprise Linux 8 and RHEL Advanced Virtualization.

It is worth noting that although qemu-kvm is built with SLiRP networking support, due to its limitations, it is not used by the virtual machine guests by default.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.